Machines may be used to move earth, rocks, and other materials from an excavation site. Often, it may be desirable to move excavated material from an excavation site to another location sufficiently removed from the excavation site that the material must be transported some distance before being dumped. For example, the earth, rocks, and/or other materials may be loaded onto an off-highway haulage unit that may, in turn, transport the materials to a dump site. As another example, the material may be excavated by a pull pan drawn behind a tractor, and then hauled, via the pull pan, to the dump site. As a further example, a wheel tractor scraper may be used for excavating, hauling, and dumping the excavated material.
A wheel tractor scraper may be used in an operating cycle to cut material from one location during a load phase, transport the cut material to another location during a haul phase, unload the cut material during a dump phase, and return to an excavation site during a return phase to repeat the operating cycle. Depending on the nature of the operation, a fleet of machines may be employed. Several wheel tractor scrapers may be involved in an excavating operation, with, for example, one machine hauling material to a dump location, another machine traveling from the dump location to the excavating site, and still another machine in the process of loading material at the excavating site.
It may require a substantial amount of power for a wheel tractor scraper to accomplish the load phase of an operating cycle. To that end, wheel tractor scrapers may be powerfully constructed, sometimes with multiple engines. Even so, wheel tractor scrapers are sometimes assisted during the load phase by another machine. For example, wheel tractor scrapers may operate in what is generally known as the “push/pull” mode or configuration, wherein a front machine is pushed by a trailing machine, and then the loaded front machine pulls the trailing machine to assist loading the trailing machine. As another example, a wheel tractor scraper may be pushed during the load phase by a track-type tractor.
In situations where multiple machines are employed in an operation, e.g., an excavating operation, the productivity of a machine and/or a fleet of machines may depend on how well one machine coordinates with other machines involved in the operation. For example, where individual machines of a fleet are operating in series to load, haul, dump, and return, efficiency and productivity may be affected by bunching of machines and resulting downtime for a given machine or machines while waiting on another machine to proceed. In addition, where one machine assists another machine in loading, for example in the push/pull mode, or when a wheel tractor scraper is pushed by a track-type tractor or another wheel tractor scraper, contact, and direct interaction while in contact, of massive and/or powerful machines may readily lead to one machine damaging another. In addition, repeated jolting contact may cause significant operator stress.
Systems have been designed with a view toward providing a communication system for multiple machines at a worksite. For example, U.S. Patent Application Publication No. 2007/0129869 A1, published on Jun. 7, 2007 (“the '869 publication”), discloses a system for autonomous cooperative control of multiple machines. The '869 publication discloses a system whereby a host machine, assigned a particular task, may broadcast a request for assistance to other machines of a fleet of machines. A machine of the fleet may then communicate to the host machine an ability or inability to provide the requested assistance. The '869 publication alludes to a situation wherein a machine may be assigned a task simply requiring two machines working in tandem, such as push-loading a scraper.
While the system of the '869 publication may provide a degree of communication among machines of a fleet and enable a degree of autonomous operation of the machines, the '869 publication does not employ a machine-to-machine communication system that effects controlled contact between two machines. The system of the '869 publication may enable sufficient communication to make available an assisting machine for push-loading a scraper, but the inherent risks of contact between the two machines may remain, and overall productivity may be compromised by machine damage and/or increased operator fatigue due, for example, to the great care operators must exercise during contact.
The present disclosure is directed to one or more improvements in the existing technology.